Tiny RNA linked to more aggressive leukemia

"If these markers are absent and TET2 gene is not mutated, then the 50 percent of leukemia patients without this marker would be spared harsher treatment such as high-dose chemotherapy or bone marrow transplants," says Jun Lu. (Credit: "blood test tubes" via Shutterstock)

A gene that helps keep blood free of cancer is controlled by tiny pieces of RNA, a finding that may lead to better ways to diagnose blood cancers and perhaps treat them.

In the past few years researchers have identified the crucial role of the gene TET2 in keeping blood cells healthy. Mutations of the gene have been found in about 20 percent of leukemias and indicate a poor prognosis for patients.

However, the gene was thought to be irrelevant in 80 percent of leukemia cases.

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The new study, published in the journal Cell Reports, changes this view. The researchers identified the agents that could be responsible for many leukemias without TET2 mutation—a host of microRNAs from the large expanse of DNA that do not code for proteins.

They found that patients with large numbers of these microRNAs are more likely to have impaired TET2 function, even without a known mutation, and are thus likely to have aggressive forms of cancer.

This knowledge could help doctors develop a course of treatment for leukemia patients, says Jun Lu, assistant professor of genetics at Yale University and a researcher in the Yale Stem Cell Center and Yale Cancer Center.

Half of leukemia patients who lack these markers may be spared side effects of aggressive treatments.

“If these markers are absent and TET2 gene is not mutated, then the 50 percent of leukemia patients without this marker would be spared harsher treatment such as high-dose chemotherapy or bone marrow transplants,” Lu says.

New therapies that could block these microRNAs could in theory help treat blood cancers.

“However, there is currently no good way to do that, but it is a problem I am very hopeful will be resolved.”